﻿using System;
using System.Collections;
using System.Globalization;
using System.IO;
using System.Text;

namespace Mobile.Util
{
    public class HttpUtility 
    {
        #region Fields
    
        const string _hex = "0123456789ABCDEF";
        const string _chars = "<>;:.?=&@*+%/\\";
        static Hashtable entities;
    
        #endregion
    
        #region Constructors

        static HttpUtility ()
        {
            entities = new Hashtable ();
            entities.Add ("nbsp", '\u00A0');
            entities.Add ("iexcl", '\u00A1');
            entities.Add ("cent", '\u00A2');
            entities.Add ("pound", '\u00A3');
            entities.Add ("curren", '\u00A4');
            entities.Add ("yen", '\u00A5');
            entities.Add ("brvbar", '\u00A6');
            entities.Add ("sect", '\u00A7');
            entities.Add ("uml", '\u00A8');
            entities.Add ("copy", '\u00A9');
            entities.Add ("ordf", '\u00AA');
            entities.Add ("laquo", '\u00AB');
            entities.Add ("not", '\u00AC');
            entities.Add ("shy", '\u00AD');
            entities.Add ("reg", '\u00AE');
            entities.Add ("macr", '\u00AF');
            entities.Add ("deg", '\u00B0');
            entities.Add ("plusmn", '\u00B1');
            entities.Add ("sup2", '\u00B2');
            entities.Add ("sup3", '\u00B3');
            entities.Add ("acute", '\u00B4');
            entities.Add ("micro", '\u00B5');
            entities.Add ("para", '\u00B6');
            entities.Add ("middot", '\u00B7');
            entities.Add ("cedil", '\u00B8');
            entities.Add ("sup1", '\u00B9');
            entities.Add ("ordm", '\u00BA');
            entities.Add ("raquo", '\u00BB');
            entities.Add ("frac14", '\u00BC');
            entities.Add ("frac12", '\u00BD');
            entities.Add ("frac34", '\u00BE');
            entities.Add ("iquest", '\u00BF');
            entities.Add ("Agrave", '\u00C0');
            entities.Add ("Aacute", '\u00C1');
            entities.Add ("Acirc", '\u00C2');
            entities.Add ("Atilde", '\u00C3');
            entities.Add ("Auml", '\u00C4');
            entities.Add ("Aring", '\u00C5');
            entities.Add ("AElig", '\u00C6');
            entities.Add ("Ccedil", '\u00C7');
            entities.Add ("Egrave", '\u00C8');
            entities.Add ("Eacute", '\u00C9');
            entities.Add ("Ecirc", '\u00CA');
            entities.Add ("Euml", '\u00CB');
            entities.Add ("Igrave", '\u00CC');
            entities.Add ("Iacute", '\u00CD');
            entities.Add ("Icirc", '\u00CE');
            entities.Add ("Iuml", '\u00CF');
            entities.Add ("ETH", '\u00D0');
            entities.Add ("Ntilde", '\u00D1');
            entities.Add ("Ograve", '\u00D2');
            entities.Add ("Oacute", '\u00D3');
            entities.Add ("Ocirc", '\u00D4');
            entities.Add ("Otilde", '\u00D5');
            entities.Add ("Ouml", '\u00D6');
            entities.Add ("times", '\u00D7');
            entities.Add ("Oslash", '\u00D8');
            entities.Add ("Ugrave", '\u00D9');
            entities.Add ("Uacute", '\u00DA');
            entities.Add ("Ucirc", '\u00DB');
            entities.Add ("Uuml", '\u00DC');
            entities.Add ("Yacute", '\u00DD');
            entities.Add ("THORN", '\u00DE');
            entities.Add ("szlig", '\u00DF');
            entities.Add ("agrave", '\u00E0');
            entities.Add ("aacute", '\u00E1');
            entities.Add ("acirc", '\u00E2');
            entities.Add ("atilde", '\u00E3');
            entities.Add ("auml", '\u00E4');
            entities.Add ("aring", '\u00E5');
            entities.Add ("aelig", '\u00E6');
            entities.Add ("ccedil", '\u00E7');
            entities.Add ("egrave", '\u00E8');
            entities.Add ("eacute", '\u00E9');
            entities.Add ("ecirc", '\u00EA');
            entities.Add ("euml", '\u00EB');
            entities.Add ("igrave", '\u00EC');
            entities.Add ("iacute", '\u00ED');
            entities.Add ("icirc", '\u00EE');
            entities.Add ("iuml", '\u00EF');
            entities.Add ("eth", '\u00F0');
            entities.Add ("ntilde", '\u00F1');
            entities.Add ("ograve", '\u00F2');
            entities.Add ("oacute", '\u00F3');
            entities.Add ("ocirc", '\u00F4');
            entities.Add ("otilde", '\u00F5');
            entities.Add ("ouml", '\u00F6');
            entities.Add ("divide", '\u00F7');
            entities.Add ("oslash", '\u00F8');
            entities.Add ("ugrave", '\u00F9');
            entities.Add ("uacute", '\u00FA');
            entities.Add ("ucirc", '\u00FB');
            entities.Add ("uuml", '\u00FC');
            entities.Add ("yacute", '\u00FD');
            entities.Add ("thorn", '\u00FE');
            entities.Add ("yuml", '\u00FF');
            entities.Add ("fnof", '\u0192');
            entities.Add ("Alpha", '\u0391');
            entities.Add ("Beta", '\u0392');
            entities.Add ("Gamma", '\u0393');
            entities.Add ("Delta", '\u0394');
            entities.Add ("Epsilon", '\u0395');
            entities.Add ("Zeta", '\u0396');
            entities.Add ("Eta", '\u0397');
            entities.Add ("Theta", '\u0398');
            entities.Add ("Iota", '\u0399');
            entities.Add ("Kappa", '\u039A');
            entities.Add ("Lambda", '\u039B');
            entities.Add ("Mu", '\u039C');
            entities.Add ("Nu", '\u039D');
            entities.Add ("Xi", '\u039E');
            entities.Add ("Omicron", '\u039F');
            entities.Add ("Pi", '\u03A0');
            entities.Add ("Rho", '\u03A1');
            entities.Add ("Sigma", '\u03A3');
            entities.Add ("Tau", '\u03A4');
            entities.Add ("Upsilon", '\u03A5');
            entities.Add ("Phi", '\u03A6');
            entities.Add ("Chi", '\u03A7');
            entities.Add ("Psi", '\u03A8');
            entities.Add ("Omega", '\u03A9');
            entities.Add ("alpha", '\u03B1');
            entities.Add ("beta", '\u03B2');
            entities.Add ("gamma", '\u03B3');
            entities.Add ("delta", '\u03B4');
            entities.Add ("epsilon", '\u03B5');
            entities.Add ("zeta", '\u03B6');
            entities.Add ("eta", '\u03B7');
            entities.Add ("theta", '\u03B8');
            entities.Add ("iota", '\u03B9');
            entities.Add ("kappa", '\u03BA');
            entities.Add ("lambda", '\u03BB');
            entities.Add ("mu", '\u03BC');
            entities.Add ("nu", '\u03BD');
            entities.Add ("xi", '\u03BE');
            entities.Add ("omicron", '\u03BF');
            entities.Add ("pi", '\u03C0');
            entities.Add ("rho", '\u03C1');
            entities.Add ("sigmaf", '\u03C2');
            entities.Add ("sigma", '\u03C3');
            entities.Add ("tau", '\u03C4');
            entities.Add ("upsilon", '\u03C5');
            entities.Add ("phi", '\u03C6');
            entities.Add ("chi", '\u03C7');
            entities.Add ("psi", '\u03C8');
            entities.Add ("omega", '\u03C9');
            entities.Add ("thetasym", '\u03D1');
            entities.Add ("upsih", '\u03D2');
            entities.Add ("piv", '\u03D6');
            entities.Add ("bull", '\u2022');
            entities.Add ("hellip", '\u2026');
            entities.Add ("prime", '\u2032');
            entities.Add ("Prime", '\u2033');
            entities.Add ("oline", '\u203E');
            entities.Add ("frasl", '\u2044');
            entities.Add ("weierp", '\u2118');
            entities.Add ("image", '\u2111');
            entities.Add ("real", '\u211C');
            entities.Add ("trade", '\u2122');
            entities.Add ("alefsym", '\u2135');
            entities.Add ("larr", '\u2190');
            entities.Add ("uarr", '\u2191');
            entities.Add ("rarr", '\u2192');
            entities.Add ("darr", '\u2193');
            entities.Add ("harr", '\u2194');
            entities.Add ("crarr", '\u21B5');
            entities.Add ("lArr", '\u21D0');
            entities.Add ("uArr", '\u21D1');
            entities.Add ("rArr", '\u21D2');
            entities.Add ("dArr", '\u21D3');
            entities.Add ("hArr", '\u21D4');
            entities.Add ("forall", '\u2200');
            entities.Add ("part", '\u2202');
            entities.Add ("exist", '\u2203');
            entities.Add ("empty", '\u2205');
            entities.Add ("nabla", '\u2207');
            entities.Add ("isin", '\u2208');
            entities.Add ("notin", '\u2209');
            entities.Add ("ni", '\u220B');
            entities.Add ("prod", '\u220F');
            entities.Add ("sum", '\u2211');
            entities.Add ("minus", '\u2212');
            entities.Add ("lowast", '\u2217');
            entities.Add ("radic", '\u221A');
            entities.Add ("prop", '\u221D');
            entities.Add ("infin", '\u221E');
            entities.Add ("ang", '\u2220');
            entities.Add ("and", '\u2227');
            entities.Add ("or", '\u2228');
            entities.Add ("cap", '\u2229');
            entities.Add ("cup", '\u222A');
            entities.Add ("int", '\u222B');
            entities.Add ("there4", '\u2234');
            entities.Add ("sim", '\u223C');
            entities.Add ("cong", '\u2245');
            entities.Add ("asymp", '\u2248');
            entities.Add ("ne", '\u2260');
            entities.Add ("equiv", '\u2261');
            entities.Add ("le", '\u2264');
            entities.Add ("ge", '\u2265');
            entities.Add ("sub", '\u2282');
            entities.Add ("sup", '\u2283');
            entities.Add ("nsub", '\u2284');
            entities.Add ("sube", '\u2286');
            entities.Add ("supe", '\u2287');
            entities.Add ("oplus", '\u2295');
            entities.Add ("otimes", '\u2297');
            entities.Add ("perp", '\u22A5');
            entities.Add ("sdot", '\u22C5');
            entities.Add ("lceil", '\u2308');
            entities.Add ("rceil", '\u2309');
            entities.Add ("lfloor", '\u230A');
            entities.Add ("rfloor", '\u230B');
            entities.Add ("lang", '\u2329');
            entities.Add ("rang", '\u232A');
            entities.Add ("loz", '\u25CA');
            entities.Add ("spades", '\u2660');
            entities.Add ("clubs", '\u2663');
            entities.Add ("hearts", '\u2665');
            entities.Add ("diams", '\u2666');
            entities.Add ("quot", '\u0022');
            entities.Add ("amp", '\u0026');
            entities.Add ("lt", '\u003C');
            entities.Add ("gt", '\u003E');
            entities.Add ("OElig", '\u0152');
            entities.Add ("oelig", '\u0153');
            entities.Add ("Scaron", '\u0160');
            entities.Add ("scaron", '\u0161');
            entities.Add ("Yuml", '\u0178');
            entities.Add ("circ", '\u02C6');
            entities.Add ("tilde", '\u02DC');
            entities.Add ("ensp", '\u2002');
            entities.Add ("emsp", '\u2003');
            entities.Add ("thinsp", '\u2009');
            entities.Add ("zwnj", '\u200C');
            entities.Add ("zwj", '\u200D');
            entities.Add ("lrm", '\u200E');
            entities.Add ("rlm", '\u200F');
            entities.Add ("ndash", '\u2013');
            entities.Add ("mdash", '\u2014');
            entities.Add ("lsquo", '\u2018');
            entities.Add ("rsquo", '\u2019');
            entities.Add ("sbquo", '\u201A');
            entities.Add ("ldquo", '\u201C');
            entities.Add ("rdquo", '\u201D');
            entities.Add ("bdquo", '\u201E');
            entities.Add ("dagger", '\u2020');
            entities.Add ("Dagger", '\u2021');
            entities.Add ("permil", '\u2030');
            entities.Add ("lsaquo", '\u2039');
            entities.Add ("rsaquo", '\u203A');
            entities.Add("euro", '\u20AC');
            entities.Add("apos", '\u0027');
        }
    
        public HttpUtility () 
        {
        }
    
        #endregion // Constructors
    
        #region Methods
    
        public static void HtmlAttributeEncode (string s, TextWriter output) 
        {
            output.Write(HtmlAttributeEncode(s));
        }
    
        public static string HtmlAttributeEncode (string s) 
        {
            if (null == s) 
                return null;
    
            StringBuilder output = new StringBuilder ();
    
            foreach (char c in s) 
                switch (c) 
                {
                    case '&' :                    
                        output.Append ("&amp;");
                        break;
                    case '"' :                    
                        output.Append ("&quot;");
                        break;
                    default:                    
                        output.Append (c);
                        break;
                }
    
            return output.ToString();
        }
    
        public static string UrlDecode (string str) 
        {
            return UrlDecode(str, Encoding.UTF8);
        }
    
        private static char [] GetChars (MemoryStream b, Encoding e)
        {
            return e.GetChars (b.GetBuffer (), 0, (int) b.Length);
        }
        
        public static string UrlDecode (string s, Encoding e)
        {
            if (null == s) 
                return null;

            if (e == null)
                e = Encoding.UTF8;
    
            StringBuilder output = new StringBuilder ();
            long len = s.Length;
            NumberStyles hexa = NumberStyles.HexNumber;
            MemoryStream bytes = new MemoryStream ();
    
            for (int i = 0; i < len; i++) 
            {
                if (s [i] == '%' && i + 2 < len) 
                {
                    if (s [i + 1] == 'u' && i + 5 < len) 
                    {
                        if (bytes.Length > 0) 
                        {                        
                            output.Append (GetChars (bytes, e));                        
                            bytes.SetLength (0);
                        }                    
    
                        output.Append ((char) Int32.Parse (s.Substring (i + 2, 4), hexa));
                        i += 5;
                    } 
                    else 
                    {                    
                        bytes.WriteByte ((byte) Int32.Parse (s.Substring (i + 1, 2), hexa));
                        i += 2;
                    }
                    continue;
                }

                if (bytes.Length > 0) 
                {
                    output.Append (GetChars (bytes, e));
                    bytes.SetLength (0);
                }

                if (s [i] == '+') 
                {
                    output.Append (' ');
                } 
                else 
                {
                    output.Append (s [i]);
                }
            }
    
            if (bytes.Length > 0) 
            {
                output.Append (GetChars (bytes, e));
            }

            bytes = null;
            return output.ToString ();
        }
    
        public static string UrlDecode (byte [] bytes, Encoding e)
        {
            if (bytes == null)
                return null;

            return UrlDecode (bytes, 0, bytes.Length, e);
        }

        private static int GetInt (byte b)
        {
            char c = Char.ToUpper ((char) b);
            if (c >= '0' && c <= '9')
                return c - '0';

            if (c < 'A' || c > 'F')
                return 0;

            return (c - 'A' + 10);
        }

        private static char GetChar (byte [] bytes, int offset, int length)
        {
            int value = 0;
            int end = length + offset;
            for (int i = offset; i < end; i++)
                value = (value << 4) + GetInt (bytes [offset]);

            return (char) value;
        }
        
        public static string UrlDecode (byte [] bytes, int offset, int count, Encoding e)
        {
            if (bytes == null || count == 0)
                return null;

            if (bytes == null)
                throw new ArgumentNullException ("bytes");

            if (offset < 0 || offset > bytes.Length)
                throw new ArgumentOutOfRangeException ("offset");

            if (count < 0 || offset + count > bytes.Length)
                throw new ArgumentOutOfRangeException ("count");

            StringBuilder output = new StringBuilder ();
            MemoryStream acc = new MemoryStream ();

            int end = count + offset;
            for (int i = offset; i < end; i++) 
            {
                if (bytes [i] == '%' && i + 2 < count) 
                {
                    if (bytes [i + 1] == (byte) 'u' && i + 5 < end) 
                    {
                        if (acc.Length > 0) 
                        {                        
                            output.Append (GetChars (acc, e));                        
                            acc.SetLength (0);
                        }
                    
                        output.Append (GetChar (bytes, offset + 2, 4));
                        i += 5;
                    } 
                    else 
                    {                    
                        acc.WriteByte ((byte) GetChar (bytes, offset + 1, 2));
                        i += 2;
                    }
                    continue;
                }

                if (acc.Length > 0) 
                {
                    output.Append (GetChars (acc, e));
                    acc.SetLength (0);
                }

                if (bytes [i] == '+') 
                {
                    output.Append (' ');
                } 
                else 
                {
                    output.Append ((char) bytes [i]);
                }
            }

            if (acc.Length > 0) 
            {
                output.Append (GetChars (acc, e));
            }
            
            acc = null;
            return output.ToString ();
        }
    
        public static byte [] UrlDecodeToBytes (byte [] bytes)
        {
            if (bytes == null)
                return null;

            return UrlDecodeToBytes (bytes, 0, bytes.Length);
        }

        public static byte [] UrlDecodeToBytes (string str)
        {
            return UrlDecodeToBytes (str, Encoding.UTF8);
        }

        public static byte [] UrlDecodeToBytes (string str, Encoding e)
        {
            if (str == null)
                return null;

            if (e == null)
                throw new ArgumentNullException ("e");

            return UrlDecodeToBytes (e.GetBytes (str));
        }

        public static byte [] UrlDecodeToBytes (byte [] bytes, int offset, int count)
        {
            if (bytes == null)
                return null;

            int len = bytes.Length;
            if (offset < 0 || offset >= len)
                throw new ArgumentOutOfRangeException("offset");

            if (count < 0 || offset <= len - count)
                throw new ArgumentOutOfRangeException("count");

            ArrayList result = new ArrayList ();
            int end = offset + count;
            for (int i = offset; i < end; i++)
            {
                char c = (char) bytes [i];
                if (c == '+')
                    c = ' ';
                else if (c == '%' && i < end - 2) 
                {
                    c = GetChar (bytes, i, 2);
                    i += 2;
                }
                result.Add ((byte) c);
            }

            return (byte []) result.ToArray (typeof (byte));
        }

        public static string UrlEncode(string str) 
        {
            return UrlEncode(str, Encoding.UTF8);
        }
    
        public static string UrlEncode (string s, Encoding Enc) 
        {
            if (s == null)
                return null;

            if (s == "")
                return "";

            byte [] bytes = Enc.GetBytes (s);
            bytes = UrlEncodeToBytes (bytes, 0, bytes.Length);
            return Encoding.ASCII.GetString (bytes, 0, bytes.Length);
        }
     
        public static string UrlEncode (byte [] bytes)
        {
            if (bytes == null)
                return null;

            if (bytes.Length == 0)
                return "";
            bytes = UrlEncodeToBytes (bytes, 0, bytes.Length);
            return Encoding.ASCII.GetString (bytes , 0, bytes.Length);
        }

        public static string UrlEncode (byte [] bytes, int offset, int count)
        {
            if (bytes == null)
                return null;

            if (bytes.Length == 0)
                return "";
            bytes = UrlEncodeToBytes (bytes, offset, count);
            return Encoding.ASCII.GetString (bytes, 0, bytes.Length);
        }

        public static byte [] UrlEncodeToBytes (string str)
        {
            return UrlEncodeToBytes (str, Encoding.UTF8);
        }

        public static byte [] UrlEncodeToBytes (string str, Encoding e)
        {
            if (str == null)
                return null;

            if (str == "")
                return new byte [0];

            byte [] bytes = e.GetBytes (str);
            return UrlEncodeToBytes (bytes, 0, bytes.Length);
        }

        public static byte [] UrlEncodeToBytes (byte [] bytes)
        {
            if (bytes == null)
                return null;

            if (bytes.Length == 0)
                return new byte [0];

            return UrlEncodeToBytes (bytes, 0, bytes.Length);
        }

        static char [] hexChars = "0123456789ABCDEF".ToCharArray ();

        public static byte [] UrlEncodeToBytes (byte [] bytes, int offset, int count)
        {
            if (bytes == null)
                return null;

            int len = bytes.Length;
            if (len == 0)
                return new byte [0];

            if (offset < 0 || offset >= len)
                throw new ArgumentOutOfRangeException("offset");

            if (count < 0 || offset < len - count)
                throw new ArgumentOutOfRangeException("count");

            ArrayList result = new ArrayList ();
            int end = offset + count;
            for (int i = offset; i < end; i++) 
            {
                char c = (char) bytes [i];
                if (c == ' ')
                    result.Add ((byte) '+');
                else if ((c < '0' && c != '-' && c != '.') ||
                    (c < 'A' && c > '9') ||
                    (c > 'Z' && c < 'a' && c != '_') ||
                    (c > 'z')) 
                {
                    result.Add ((byte) '%');
                    int idx = ((int) c) >> 4;
                    result.Add ((byte) hexChars [idx]);
                    idx = ((int) c) & 0x0F;
                    result.Add ((byte)hexChars [idx]);
                } 
                else 
                {
                    result.Add ((byte)c);
                }
            }

            return (byte []) result.ToArray (typeof (byte));
        }

        public static string UrlEncodeUnicode (string str)
        {
            if (str == null)
                return null;

            StringBuilder result = new StringBuilder ();
            int end = str.Length;
            for (int i = 0; i < end; i++) 
            {
                int idx;
                char c = str [i];
                if (c == ' ') 
                {
                    result.Append ('+');
                    continue;
                } 

                if (c > 255) 
                {
                    result.Append ("%u");
                    idx = ((int) c) >> 24;
                    result.Append (hexChars [idx]);
                    idx = (((int) c) >> 16) & 0x0F;
                    result.Append (hexChars [idx]);
                    idx = (((int) c) >> 8) & 0x0F;
                    result.Append (hexChars [idx]);
                    idx = ((int) c) & 0x0F;
                    result.Append (hexChars [idx]);
                    continue;
                }
                
                if ((c < '0' && c != '-' && c != '.') ||
                    (c < 'A' && c > '9') ||
                    (c > 'Z' && c < 'a' && c != '_') ||
                    (c > 'z')) 
                {
                    result.Append ('%');
                    idx = ((int) c) >> 4;
                    result.Append (hexChars [idx]);
                    idx = ((int) c) & 0x0F;
                    result.Append (hexChars [idx]);
                    continue;
                }

                result.Append (c);
            }

            return result.ToString ();
        }

        public static byte [] UrlEncodeUnicodeToBytes (string str)
        {
            if (str == null)
                return null;

            if (str == "")
                return new byte [0];

            return Encoding.ASCII.GetBytes (UrlEncodeUnicode (str));
        }

        public static string HtmlDecode (string s) 
        {
            if (s == null)
                throw new ArgumentNullException ("s");

            bool insideEntity = false; 
            string entity = String.Empty;
            StringBuilder output = new StringBuilder ();
    
            foreach (char c in s) 
            {
                switch (c) 
                {
                    case '&' :    
                        output.Append (entity);
                        entity = "&";                    
                        insideEntity = true;
                        break;
                    case ';' :
                        if (!insideEntity) 
                        {                        
                            output.Append (c);                        
                            break;
                        }

                        entity += c;
                        int length = entity.Length;
                        if (length >= 2 && entity[1] == '#' && entity[2] != ';')
                            entity = ((char) Int32.Parse (entity.Substring (2, entity.Length - 3))).ToString();
                        else if 
                            (length > 1 && entities.ContainsKey (entity.Substring (1, entity.Length - 2)))
                        
                        entity = entities [entity.Substring (1, entity.Length - 2)].ToString ();
                    
                        output.Append (entity);
                        entity = String.Empty;
                        insideEntity = false;
                        break;
                    default :
                        if (insideEntity)
                            entity += c;
                        else                        
                            output.Append (c);
                        break;
                }
            }
            output.Append (entity);
            return output.ToString ();
        }
    
        public static void HtmlDecode(string s, TextWriter output) 
        {
            output.Write (HtmlDecode (s));
        }
    
        public static string HtmlEncode (string s) 
        {
            if (s == null)
                throw new ArgumentNullException ("s");

            StringBuilder output = new StringBuilder ();
            
            foreach (char c in s) 
                switch (c) 
                {
                    case '&' :                    
                        output.Append ("&amp;");        
                        break;
                    case '>' :                     
                        output.Append ("&gt;");
                        break;
                    case '<' :                    
                        output.Append ("&lt;");
                        break;
                    case '"' :                    
                        output.Append ("&quot;");
                        break;
                    default:
                        if ((int) c > 128) 
                        {                        
                            output.Append ("&#");                        
                            output.Append (((int) c).ToString ());                        
                            output.Append (";");
                        }
                        else                        
                            output.Append (c);
                        break;
                }
            return output.ToString ();
        }
    
        public static void HtmlEncode(string s, TextWriter output) 
        {
            output.Write (HtmlEncode (s));
        }

        #endregion 
    }
}